In a vehicle to vehicle (V2V, Vechicle to Vechicle) communications system, any vehicle may exchange data with a surrounding vehicle in a broadcast or unicast manner. A device sends V2V information in the broadcast manner, so as to effectively transfer information and improve network flexibility. The V2V information is periodic broadcast information, and includes vehicle status information such as a device identifier, a device location, a speed, an acceleration, or a running route.
In the V2V communications system, after entering a region, a vehicle sends a periodic signal of the vehicle according to a transmission pattern, and receives a periodic signal sent by another vehicle, so that vehicles can find each other.
The vehicle in the V2V communications system may send or receive the periodic signal in the region by using the transmission pattern. However, in the prior art, a vehicle may randomly select a resource to send the periodic signal, and this cannot ensure that vehicles close to each other can find each other when the resource is selected. As a result, an occurrence probability of an accident is relatively high. In addition, if after all vehicles between two vehicles that cannot find each other leave the region, and the two vehicles still cannot find each other, it is very likely that an accident occurs.